In the case where gear shift is performed in the vehicle equipped with the engine and the manual transmission, the driver usually disengages a clutch. Thus, the rotational force generated by the engine is stopped from a crankshaft of the engine to a main axis of the manual transmission, thereby facilitating the separation of a gear and a dog. In the cut state where the clutch is disengaged, the driver performs the shift operation and changes the gear position. Finally, the driver engages the clutch to transmit the rotational force from the crankshaft to the main axis. This completes the gear shift.
If the output of the engine is appropriately adjusted at the time of the gear shift, the gear shift is performed without the clutch operation by the driver described above (hereinafter referred to as “no-clutch operation”) and a high operability is obtained. A control technique for automatic changing of the gear position with the no-clutch operation in the vehicle is proposed. For example, in the vehicle according to Japanese Patent No. 5041974, a shift up of the gear position is smoothly carried out by lowering the output of the engine in the drive state which is transmitted from the engine to the manual transmission. Conversely, the gear position is smoothly shifted by increasing the output of the engine in the driven state which is transmitted from the manual transmission to the engine from the manual transmission.
As described above, the shift up when a driving area of the vehicle is in the traveling state and the shift down when the driving condition is driven can be controlled favorably. However, the control of changing the gear positions in the other driving areas is not always easy, and it is very difficult to smoothly change the gear positions with the no-clutch operation for the shift down during the acceleration and for the shift up during the deceleration as the shift operation by the driver. Therefore, in such a case, a technology capable of smoothly performing shift operation with the no-clutch operation is desired.